• Title/Summary/Keyword: chemical oxide

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Ozonolyses of Cycloalkenes: Trapping of Carbonyl Oxide by Trifluoroacetophenone

  • 이주연;이치원;허태성
    • Bulletin of the Korean Chemical Society
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    • v.19 no.11
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    • pp.1244-1248
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    • 1998

  • Ozonolysis reactions of cyclic olefins 1a-c and norbomene In in the presence of trifluoroactophenone 6 provided the corresponding cross-ozonides 7a-c and 7n. Further reactions of ozonides 7a-c and 7n with the independently prepared carbonyl oxide 11 gave diozonides of structure l0a-c and 10n. The ozonolysis of 1methylcyclopentene 12a and 1-methylcyclohexene 12b in the presence of trifluoroactophenone 6 provided exclusively ozonide 15 and 16 derived from capture of carbonyl oxide 13. All of the new ozonides have been isolated as pure substances and characterized by their 1H NMR and 13C NMR spectra.

  • https://doi.org/10.5012/bkcs.1998.19.11.1244 인용 PDF

Surface Modification of Iron Oxide Particle by Silica-contained Materials (실리카계 물질에 의한 산화철 입자의 표면개질)

  • Ryu, Beyong-Hwan;Lee, Jung-Min;Koh, Jae-Cheon
    • Applied Chemistry for Engineering
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    • v.8 no.5
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    • pp.830-836
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    • 1997

  • The surface modification of iron oxide particle produced from steel-pickled acid by sodium-contained materials was studied. The molar ratio of $SiO_2$ to $Na_2O$ of sodium silicate was 1, 2, 3.5, respectively. The dispersion stability of iron oxide suspension as functions of amount of silica and pH was evaluated by surface charge and sedimentation velocity of iron oxide particle. Then the amount of sodium silicate was determined to provide a dispersion stability of iron oxide particle above pH 7. Finally, the surface modification of iron oxide particle with sodium silicate as silica-contained materials was done by wet ball milling. In the results of study, the dispersion stability of silica modified iron oxide particle was largely depended on amount of silica and pH together. The untreated iron oxide was unstable at pH 8, i.e. isoelectric point, but, the surface modified iron oxide particle with 0.8wt% silica was stable above pH 5. The dispersion stability was enhanced with 0.2wt% of anionic polyelectrolyte.

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Structure of Oxide Film Prepared by Two-step Anodization of Aluminum

  • Ko, Eunseong;Ryu, Jaemin;Kang, Jinwook;Tak, Yongsug
    • Corrosion Science and Technology
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    • v.5 no.4
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    • pp.137-140
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    • 2006

  • The effect of pre-existing barrier-type film on porous aluminum oxide film formation during anodization was investigated to control the uniform film growth rate. Initial potential fluctuations during anodization indicated that the breakdown of barrier-film is preceded before the porous formation and the induction time for the porous film growth increases with the increases of pre-existing film thickness. The porous film growth mechanism is lot affected by the presence of barrier film on aluminum surface. In parallel, uniform growth of barrier film underneath the porous structure was attained by two-step anodization processes.

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